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Fuel Lube on Brake Line Fittings?

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rv10free2fly(at)yahoo.com
Guest

Posted: Tue Nov 10, 2009 3:05 pm Post subject: Fuel Lube on Brake Line Fittings?

Guys, could you please tell me if fuel lube should be applied to the threads on brake line fittings during installation?

  

 Kind regards from a warm down under - fours days straights of 100F, at least there's no snow!

  

 Patrick Pulis

 Adelaide, South Australia



 

   From: Bob Leffler <rv(at)thelefflers.com>

To: rv10-list(at)matronics.com

Sent: Tue, 10 November, 2009 12:37:03 PM

Subject: RE: RV10-List: Question about AN Fittings



      

No, donâ€™t use Teflon.  Use fuel lube on the threads. 

  

bob 

    

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Les Kearney

Sent: Monday, November 09, 2009 8:16 PM

To: rv10-list(at)matronics.com

Subject: Question about AN Fittings



 

  

Hi 

  

I have some AN nipples that I want to install on a Matco parking brake. As these connections are not compression fittings, should I be using anything like Teflon tape on the joints? 

  

Inquiring minds need to know 

  

Les 

#40643 still in fibreglass hell but out on a day pass 	  Quote: 	
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8http://www.mearch & Download, =   --> http://www.matronics.com/Navigator?RV10-List[/url] ======    [/b][/quote]



           Win 1 of 4 Sony home entertainment packs thanks to Yahoo!7. [url=http://us.lrd.yahoo.com/_ylc=X3oDMTJxN2x2ZmNpBF9zAzIwMjM2MTY2MTMEdG1fZG1lY2gDVGV4dCBMaW5rBHRtX2xuawNVMTEwMzk3NwR0bV9uZXQDWWFob28hBHRtX3BvcwN0YWdsaW5lBHRtX3BwdHkDYXVueg--/SIG=14600t3ni/**http%3A//au.rd.yahoo.com/mail/tagline/sony/*http%3A//au.docs.yahoo.com/homepageset/%3Fp1=other%26p2=au%26p3=mailtagline]Enter now[/url].

jeff(at)westcottpress.com
Guest

Posted: Tue Nov 10, 2009 4:01 pm Post subject: Fuel Lube on Brake Line Fittings?

That's what I was advised to do and what I have done... for what little that is worth.



Jeff Carpenter

40304



On Nov 10, 2009, at 2:35 PM, Patrick Pulis wrote:

 	  Quote: 	
		  Guys, could you please tell me if fuel lube should be applied to the threads on brake line fittings during installation?

 

Kind regards from a warm down under - fours days straights of 100F, at least there's no snow!

 

Patrick Pulis

Adelaide, South Australia

From: Bob Leffler <rv(at)thelefflers.com (rv(at)thelefflers.com)>

To: rv10-list(at)matronics.com (rv10-list(at)matronics.com)

Sent: Tue, 10 November, 2009 12:37:03 PM

Subject: RE: Question about AN Fittings



No, don’t use Teflon.  Use fuel lube on the threads.



 bob



 From: owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com) [mailto:owner-rv10-list-server(at)matronics.com (owner-rv10-list-server(at)matronics.com)] On Behalf Of Les Kearney

Sent: Monday, November 09, 2009 8:16 PM

To: rv10-list(at)matronics.com (rv10-list(at)matronics.com)

Subject: Question about AN Fittings



 Hi



 I have some AN nipples that I want to install on a Matco parking brake. As these connections are not compression fittings, should I be using anything like Teflon tape on the joints?



 Inquiring minds need to know



 Les

#40643 still in fibreglass hell but out on a day pass

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8www.buildersbowww.matronics.com/contribution" target=_blank rel=nofollow>http://www.mearch & Download, = -->http://www.matronics.com/Navigator?RV10-List ======



Win 1 of 4 Sony home entertainment packs thanks to Yahoo!7. [url=http://us.lrd.yahoo.com/_ylc=X3oDMTJxN2x2ZmNpBF9zAzIwMjM2MTY2MTMEdG1fZG1lY2gDVGV4dCBMaW5rBHRtX2xuawNVMTEwMzk3NwR0bV9uZXQDWWFob28hBHRtX3BvcwN0YWdsaW5lBHRtX3BwdHkDYXVueg--/SIG=14600t3ni/**http%3A//au.rd.yahoo.com/mail/tagline/sony/*http%3A//au.docs.yahoo.com/homepageset/%3Fp1=other%26p2=au%26p3=mailtagline]Enter now[/url]. 	  Quote: 	
		  	
9



	


 [quote][b]

rleffler

Joined: 05 Nov 2006
Posts: 680

Posted: Tue Nov 10, 2009 5:19 pm Post subject: Fuel Lube on Brake Line Fittings?

Itâ€™s certainly easier than after installation.Â  :^)Â Â  I had to beat Rick to the punch.  

   

I applied fuel lube to the threads of all my brake fittings.  

       

From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Patrick Pulis

 Sent: Tuesday, November 10, 2009 5:36 PM

 To: rv10-list(at)matronics.com

 Subject: Fuel Lube on Brake Line Fittings?  

  

  

       

Guys, could you please tell me if fuel lube should be applied to the threads on brake line fittings during installation?  

    

   

    

Kind regards from a warm down under - fours days straights of 100F, at least there's no snow!  

    

   

    

Patrick Pulis  

    

Adelaide, South Australia  

    

   

  

  

       [quote][b]

_________________
Bob Leffler
N410BL - Phase I
http://mykitlog.com/rleffler

AirMike

Joined: 27 Feb 2007
Posts: 514
Location: Nevada

Posted: Tue Nov 10, 2009 7:33 pm Post subject: Fuel Lube on Brake Line Fittings?

I used fuel lube on my brake line fittings and had good luck with all except two fittings at my Matco (after market) parking brake. I had one heck of a leak (very messy brake fluid) on the floor of the pilot footwell. It was a real mess. I finally used Permatex non-hardening sealant on these fittings and finally got the leak sealed. If you do not have a parking brake just use the fuel lube. If you have the Matco parking brake valve (I love it) use Permatex on those fittings. I think that it is Permatex #2 but not sure - it is a non-soluble sealant. 



See my prior post (over 1 year ago) on the Matco brake.

_________________
See you OSH '18
Q/B - sold.

kearney

Joined: 20 Sep 2008
Posts: 563

Posted: Tue Nov 10, 2009 9:52 pm Post subject: Fuel Lube on Brake Line Fittings?

Hmmm  

This has been an interesting thread. When I asked the original question, I was referring to (and I hate to use this work again because of Rick Sked <vbg>) the NPT nipples to be installed on the front of the Matco parking brake. These do not have a compression fitting on the Matco side.  

  

I was not referring to the compression fittings. My understanding was that compression fittings do not need any extra "help" in sealing when done correctly.   

Anyway, this is what I found on Wikipedia:  

Joint compound or Thread seal tape (a.k.a. PTFE tape, Teflon tape) is not applied to a compression fitting's threads. The compression is the means of sealing the joint, not the sealing of the threads themselves. Pipe compound or PTFE tape frequently leads to a leaks in the fitting because it allows a gap to form between the compression ring and nut in the case of Teflon tape. Joint compound is usually applied to the ferrule or olive to seal imperfections in the fitting, but really serves no purpose as the sealing is enacted through the compression ring itself; if the compression ring indeed becomes "ovalled" because it is overtightened when it is in a misoriented position in relation to the compression nut or there is some factory defect in the product, rarely does joint compound (pipe "dope") or Teflon tape compensate for the loss of an air/watertight seal. In this instance, the compression fitting are simply replaced. Joint compound and Teflon tape act to seal the threads from the water pressure in normal threaded connections, but serve little purpose in compression seals and may actually serve to weaken them.  

  

It sounds like fuel lube etc may actually increase the change of leaks by adversely impacting the compression of the pipe flare against the AN fitting.  

AC43.13 (page 9-1 does suggest using hydraulic fluid as a lubricant when tightening but makes no mention of anything like a sealant such as fuel lube.  

Cheers  

Les  

#40643 - Still in fibreglass hell but on a day pass  

  

--

Kelly McMullen

Joined: 16 Apr 2008
Posts: 1188
Location: Sun Lakes AZ

Posted: Wed Nov 11, 2009 4:28 am Post subject: Fuel Lube on Brake Line Fittings?

Les,

I believe most respondents interpreted your question correctly, and

were answering what to use on the NPT threads, not the flare fittings.

PTFE tape is to be avoided, because it leaves threads of PTFE on the

fitting when removed, and can migrate into the system when

reassembled. Fuel lube serves as a sealant that is not soluble in

typical hydrocarbon fluids. Pipe seal paste can be used, but residue

left on dis-assembly is still a concern.

Kelly



On Tue, Nov 10, 2009 at 10:49 PM, Les Kearney <kearney(at)shaw.ca> wrote:

 	  Quote: 	
		   Hmmm



 This has been an interesting thread. When I asked the original question, I

 was referring to (and I hate to use this work again because of Rick Sked

 <vbg>) the NPT nipples to be installed on the front of the Matco parking

 brake. These do not have a compression fitting on the Matco side.



 I was not referring to the compression fittings. My understanding was that

 compression fittings do not need any extra "help" in sealing when done

 correctly.

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor
KCHD

MauleDriver(at)nc.rr.com
Guest

Posted: Wed Nov 11, 2009 5:19 am Post subject: Fuel Lube on Brake Line Fittings?

For the panel builders, I found EZ Lube to be just the right stuff to 

dab on the end of a screwdriver to hold those pesky screws in place.  

Very handy.

pitts_pilot(at)bellsouth.
Guest

Posted: Wed Nov 11, 2009 6:31 am Post subject: Fuel Lube on Brake Line Fittings?

Les, I'm still confused here.  You said you were not referring to 

compression fittings, but your Wiki example was .... compression fittings.



So,let's start by dividing the fittings.  Compression fittings are used 

on tubing without a flare.  I've never seen blue anodized compression 

fittings ..... but that doesn't mean they don't exist.  Compression 

fittings are typically brass, and found in the aviation isle of Ace and 

others.  They need no pipe dope or teflon tape on the compression side 

or the NPT (National Pipe Thread)side, but some lubrication with fuel 

lube or brake fluid can't hurt.  The rest of the fittings we, in 

aviation, use are 'AN' fittings, and come in steel, and in blue or red 

anodized aluminum.  The flare fitting gets it's seal from mashing the 

flared tubing between the fitting and a sleeve, pressure applied by a 

"B" nut. This isn't your standard hardware store 45 degree flare.  It's 

a 37 degree JIC flare, and is standard in hydraulic applications. This 

joint doesn't NEED anything else, but some lubrication doesn't hurt.



Now onto the fitting side.  Since we've covered flare fittings .... and 

some AN fittings have flares on both sides, we're going to focus on 

those fittings that screw into something hard, like an aluminum block. 

These fittings use NPT (National Pipe Thread) which is a tapered thread. 

  This NPT fitting doesn't usually need anything to seal it.  Sealing is 

done in the taper.  Leaks are caused by poor threading .... either the 

fitting, or the part it's screwed into.



After all that, what about Teflon tape, or Teflon pipe dope?  Why use 

it?  You have a leak???  Well, the fitting isn't tight enough .... 

either in the taper thread side, or the "B" nut side, or there's a 

manufacturing problem.  But, you still want to put something in there. I 

don't know why, but you do.  Teflon tape isn't recommended since it can 

migrate into the tubing because when you've changed the fitting, and 

some string of Teflon tape got pushed into the hole .... and plugs 

something up down the line.  Pipe dope isn't recommended for the same 

reason .... but the pieces aren't big, and stand less chance of plugging 

something up.  Fuel lube or brake fluid on the threads for lubrication 

is OK, but by design the fittings are made to go together dry.

Sorry for the long post, but I want to see us be safe and fly for many 

years without damage to people or aircraft.

Linn

do not archive

Les Kearney wrote:

[quote] Hmmm

 

 This has been an interesting thread. When I asked the original question, 

 I was referring to (and I hate to use this work again because of Rick 

 Sked <vbg>) the NPT nipples to be installed on the front of the Matco 

 parking brake. These do not have a compression fitting on the Matco side.

 

 *_I was not_* referring to the compression fittings. My understanding 

 was that compression fittings do not need any extra "help" in sealing 

 when done correctly.

 

 Anyway, this is what I found on Wikipedia:

 

 /Joint compound or Thread seal tape (a.k.a. PTFE tape, Teflon tape) is 

 not applied to a compression fitting's threads. The compression is the 

 means of sealing the joint, not the sealing of the threads themselves. 

 Pipe compound or PTFE tape frequently leads to a leaks in the fitting 

 because it allows a gap to form between the compression ring and nut in 

 the case of// Teflon// tape. Joint compound is usually applied to the 

 ferrule or olive to seal imperfections in the fitting, but really serves 

 no purpose as the sealing is enacted through the compression ring 

 itself; if the compression ring indeed becomes "ovalled" because it is 

 overtightened when it is in a misoriented position in relation to the 

 compression nut or there is some factory defect in the product, rarely 

 does joint compound (pipe "dope") or// Teflon// tape compensate for the 

 loss of an air/watertight seal. In this instance, the compression 

 fitting are simply replaced. Joint compound and// Teflon// tape act to 

 seal the threads from the water pressure in normal threaded connections, 

 but serve little purpose in compression seals and may actually serve to 

 weaken them.///

 

 It sounds like fuel lube etc may actually increase the change of leaks 

 by adversely impacting the compression of the pipe flare against the AN 

 fitting.

 

 AC43.13 (page 9-1 does suggest using hydraulic fluid as a lubricant 

 when tightening but makes no mention of anything like a sealant such as 

 fuel lube.

 

 Cheers

 

 Les

 

 #40643 - Still in fibreglass hell but on a day pass

 

 --

kearney

Joined: 20 Sep 2008
Posts: 563

Posted: Wed Nov 11, 2009 7:55 am Post subject: Fuel Lube on Brake Line Fittings?

Hi Linn



Apologies for the confusion. My original post was referring to the NPT

connections at the Matco brake. My follow up was because there were a couple

of posts recommending fuel lube on all the brake line fittings - this would

encompass the blue anodized flared compression fitting. It is my

understanding that flared fittings are a type of compression fitting

although not all compression fittings are flared. I stand to be corrected

though.



Cheers



Les

#40643 



--

pitts_pilot(at)bellsouth.
Guest

Posted: Wed Nov 11, 2009 11:51 am Post subject: Fuel Lube on Brake Line Fittings?

Now, I think I understand.  Compression fittings usually have a ..... 

barrel, thimble .... whatever your favorite is .... that deforms to seal 

on the tube, and also forms itself to the fitting and the nut.  Flare 

fittings aren't in the compression fitting category.  They seal by the 

mating flare and the surface area of the flare.  They will, in some 

cases, seal just fine with very little pressure.  Most all flare 

fittings I come across are way overtightened, and actually cause the 

flare material to flow outwards, which causes premature cracking of the 

now-thinner material.  Do not ask the gorilla to tighten the B-nuts.

Linn

do not archive

Les Kearney wrote:

[quote] 

 

 Hi Linn

 

 Apologies for the confusion. My original post was referring to the NPT

 connections at the Matco brake. My follow up was because there were a couple

 of posts recommending fuel lube on all the brake line fittings - this would

 encompass the blue anodized flared compression fitting. It is my

 understanding that flared fittings are a type of compression fitting

 although not all compression fittings are flared. I stand to be corrected

 though.

 

 Cheers

 

 Les

 #40643 

 

 --

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